Conventional bearings usually strain under a variety of severe operation conditions over long-term operation, such as heavy loading, high speed spinning, and severe environment conditions such as abnormal high or low temperature, strong vibration and the like. It could happen that lubricating media are gradually consumed and exhausted after a short period of operation. As a result of deteriorating tribology interface between peripheries of the spinning shaft and axial hole, the shaft could directly contact the axial hole to induce high frequency knocks and impacts, resulting in excessive abrasion and heat generation. This can lead to electric current increase, noise generation, shaft scraping, axial hole dilation, or shaft jam, which accelerates damage of the bearing. All of these are critical technical problems of the conventional bearing to be resolved.
To maintain smooth operation of the bearing under the aforesaid severe operation and environment conditions for a prolonged period of time requires forming a tribology interface between the peripheries of the axial hole and the spinning shaft to support the shaft. To resolve these problems, sufficient lubricating media must be evenly and smoothly replenished and recycled. Other factors, such as simplified fabrication process to facilitate mass production, desirable cooling capability of the tribology interface, sturdiness and durability of total structure, adjustability of locations and capacities of lubricating media passages and storage chamber, and flexibility of employing diversified lubricating media at the same time or individually, also are important. The aforesaid lubricating media can be any substance that can provide desired lubrication effect between the spinning shaft and axial hole of the bearing including but not limited to oil of relatively lower viscosity, lubricants of higher viscosity such as grease and hybrid lubricants contained solid lubricating grains.
US 2006/01716181A1 proposes a self-lubrication bearing with a hollow assembly coupled on a shaft. The assembly has T-shaped two-stepped cylindrical struts coupled together through a smaller end to form an indented circumference, and a hollow barrel casing coupled on the assembly to form a storage chamber between them to store lubricating oil. A gap is formed on the connection surface of the storage chamber to allow the lubricating oil to seep and flow into the axial hole. However, lubricants of a higher viscosity cannot be used on the aforesaid bearing.
US 2009/0208153A1 discloses a fluid lubricating bearing including a housing, a bearing sleeve fixed onto the housing and a shaft portion which rotates relative to the housing and the bearing sleeve. Radial hydrodynamic grooves are arranged on the inner circumferential surface of the bearing sleeve. Thrust hydrodynamic grooves are arranged on the lower and upper end face of the bearing sleeve. Also, an annular sealing space formed integrally with the side portion of the housing. While the shaft is in rotation, the lubricating oil is driven by the radial and thrust hydrodynamic grooves to flow around the outer periphery faces and the inner periphery faces of the bearing sleeve to complete the circulation loop. The bearing sleeve is the only unit to support the shaft portion and the lubricating oil is circulated one-way through the loop. Also, the bearing lacks adjustability of the locations and capacities of the lubricating oil passages and storage.
GB 1389857A discloses another type of self-lubrication bearing with a hollow cylindrical barrel made from plastics by injection to couple on a shaft. The plastic unit has a plurality of protrusive fin-shaped circular rings formed radially and spaced from each other axially, and a hollow barrel casing to couple on the circumference of the plastic unit so that adjacent circular rings form a plurality of annular storage chambers to store lubricating media. The lubricating media can seep and flow into the axial hole through multiple apertures formed in the storage chambers. The bearing made with a metal or ceramic requires other types of fabrication process have to be adopted. The structure is more complex, and mass production is more difficult.
U.S. Pat. No. 3,917,362A discloses a self-lubrication bearing formed by coupling a hollow assembly on a shaft. The assembly has an annular groove formed radially in the center of the circumferential surface. A hollow barrel casing is provided to couple on the circumferential outer surface of the assembly so that the groove forms an annular storage to store lubricating grease. The groove has a plurality of apertures formed thereon to allow the lubricating grease to seep into the axial hole.
GB 297875, EP 2333364, DE 1400440 and GB 540865 also disclose bearings including different lubricating means.
All the aforesaid conventional bearings do not provide a dynamic pressure and a lubricating media replenish and recycle mechanism.
They also lack adjustability on the locations and capacities of the lubricating media passages and storage chamber, and flexibility on employing diversified lubricating media. Their complex structures also limit miniaturization and mass production applicability, and make the costs higher and heat dissipation more difficult. Hence they are severely constrained in the applicability for the severe operation environments of abnormal high or low temperature, high spinning speed or the like. In other demanding operation environments such as high loading and strong vibration, the total structural strength is an even more important consideration.